I have a 3D model of a complete city, and would like to show an isometric view of those buildings. I use gnuplot polygons for this, since I don\'t think I can use pm3d for p
I know this is an old question, but there is now a gnuplot setting that I think will do what is asked:
set pm3d depthorder base
This sorts pm3d polygons by projecting them onto the base plane (usually z=0) and then sorting by distance from the view point. This algorithm was intended to handle simpler cases like 3D boxes, but your model is close enough being boxes-on-a-base that I think it would benefit from the same treatment. Here is an example from the "boxes3d" demo.